Portable fluid-pressure hammer.



678,759. Patented July l6, l90l. W. PAYTON.

PORTABLE FLUID PRESSURE HAMMER.

' (lyplination filed Dec. 10, 1900.)

. (Ho Model) Qmgtw UNTTED STATES PATENT UEETQE.

WALTER PAYTON, OF RICHMOND, ENGLAND.

PORTABLE FLUID-PRESSURE HAMMER.

SPECIFICATION forming part of Letters Patent No. 678,? 59, dated July 16, 1901. Application filed December 10, 1900. Serial No. 39,399. (No model.)

To all whom, it may concern:

Be it known that I, WALTER PAYTON, engineer, a subject of the Queen of Great Britain, residing at 138 Sheen road, Richmond, county of Surrey, England, have invented certain new and useful Improvements in and Relating to Portable Fluid-Pressure Hammers and Similar Tools, of which the following is a specification.

This invention relates to that class of portable fluid-pressure engines in which reciprocating pistons controlled by valves constitute hammers adapted to deliver rapid] y-recurrin g blows to a chipping or other tool located in the path of such impact-pistons; and the chief objects of the invention are to construct such engines in a simpler and more efficient manner than heretofore and to use to better advantage and with greater economy than heretofore the motive fluid by which the pistons are actuated. Engines of this kind are adapted to work by compressed air and are generally termed pneumatic hammers and as usually constructed consist of four types, to all of which my invention is equally applicable. The first type is that in which the piston has two diameters,the smaller of which reciprocates in the rear end of a cylinder and is continuously subject to the pressure of the motive fluid, while the larger diameter reciprocates in the forward end of said cylinder,the reciprocation of the said piston being obtained by alternately admitting the motive fluid to the face of its larger or forward end and exhausting it therefrom.

An important feature of my invention is the provision of the piston (whether the latter be one of the kind referred to in the first type or in the other types of engine) with a sliding or tappet valve, which is so arranged that the movement of the piston as it completes its strokes will cause the said valve to strike against suitable pieces or abutments situated within the working cylinder, and thereby move into proper position to'open and close the inlet and exhaust ports or passages and permit the motive fluid to actuate the piston, as aforesaid. It will thus be observed that in accordance with this invention the said tubular valve is not actuated directly by the fluid-pressure, as is the case in some fluid-pressure hammers heretofore proposed,

but is actuated by a percussive force due to the impact of the moving valve with the abutments, as aforesaid. These abutments do not reciprocate with the piston, but are carried by or form part of the body or cylinder of the engine. By providing for the poroussive movement of said tubular valve I can insure that it will be shifted at regular predetermined intervals in the stroke of the piston, so that the engine will work quite smoothly and without intermittent stoppages, which are liable to occur with valves actuated by the motive fluid, such intermittent stoppages being due in most cases to the cushioning efiect of the motive fluid on the valve, especially when the latter is working at a high speed.

My invention also comprises other impor tant features, which will be hereinafter re ferred to.

In the accompanying drawings I have illustrated my invention applied to the various types of pneumatic engines or hammers above referred to.

Figure 1 is a side elevation, and Figs. 2 and 3 are longitudinal sections, showing myinvention applied to the first of the above-mentioned types of pneumatic hammers. The longitudinal sections are taken in planes approximately at right angles to each other, Fig. 2 representing the piston in its retracted position ready to strike its blow, and Fig. 3 representing said piston in its forward position after having delivered its blow. Fig. i is a transverse section taken approximately on the line a z of Fig. 2.

In all the figures like letters indicate similar parts.

A is the piston, B the sliding or tappet valve, and O the body of the hammer in which said piston reciprocates.

Referring more particularly to Figs. 1 to 4,- the piston A is formed of two diameters, of which the smaller reciprocates freely, but in an air-tight manner, in a ring D. This ring is provided with a flange d, which lies be-- tween the rear end of the body 0 and a shoulder 0 of the portion 0 of the cylinder, this portion of the cylinder being provided with a screw-threaded socket to screw upon the rear end of the body 0 and securely retaining said ring (1 in place. The two portions 0 and G when thus screwed together constitute the working cylinder within which the motive fluid operates to reciprocate the piston, as hereinafter explained. The portion 0 of the cylinder is extended rearwardly, so as to form a chamber 0, into an d out of which the smaller end of the piston moves when reciprocating. This chamber is somewhat larger in diameter than the part of the piston that moves within it and is in constant communication with the motive fluid when the piston is reciprocating. The said portion 0 has formed as part of it or attached to it a transverse handle 0 to enable the apparatus to be held in the hand of the workman, and such handle is made hollow, so as to form a passage through which the motive fluid has access to the interior of the chamber 0 through the hollow arm 0 The handle is provided with a screw-threaded opening 0 or may be provided with other suitable means for coupling it to a flexible hose or pipe leading from the supply of motive fluid, and it is also provided with a regulating-valve E for controlling the flow of the motive fluid through it to the working cylinder. This valve may be of any usual or approved kind; but it is preferred to construct it of a bush 6, screwed or otherwise secured within the hollow handle contiguous to the hollow arm 6 and having therein lateral ports a, Fig. 2. Within this bush is a cylindrical plug 6 retained in place against the fluidpressure by screw-threads and adapted to turn in the said bush in an air-tight manner. Said bush has a central passage 6 and lateral ports 6, which ports can be caused to coincide with the ports 6 in the plug by turning the head or thumb piece 6 at the outer end of the said plug. The periphery of this head or thumb piece occupies such a position relatively to the handle 0 that the thumb of the hand with which the workman grasps said handle can be utilized to readily turn said head in either direction to open or close the ports 6 e and regulate the entrance of the pressure fluid to the apparatus. In order to limit the extent to which said head can be turned, it is formed with a segmental slot 6 Fig. 1, into which a stationary pin e enters and acts as a stop.

The total length of the cylinder (J G is somewhat longer than is necessary to enable the piston to make its full stroke, and the forward end is reduced in diameter in order that a tool-holder F may be fitted within the body of the cylinder and in a line with the piston. The tool-holder is cylindrical and is formed at its inner end with a head or shoulder f, which fits the cylinder 0. The outer portion of said tool-holder is of a diameter to fit the reduced part 0 of the cylinder, and its dimensions are such that when in place a space is provided between the said head f and part 0 to receive a helical spring f, which tends to press the holder a short distance into the cylinder, a stop f that engages with a longitudinal slot f being provided for limiting the extent of such distance. The said tool-holder is bored out to receive the shank of the chipping or other tool G, and the shank of the tool is preferably provided with a larger shoulder g, which lies in contact with the outer end of the holder. The shank does not pass through the holder so as to expose the inner end to the pressure of the motive fluid, as the shankin that case would be liable to be blown out of the holder unless held firmly in place by the workman. The shank is also made somewhat shorter than the hole of the holder in which it fits in order that the effect of the blow delivered by the piston (which blow is received by the inner face of the holder) instead of being imparted by the holder to the tool through the shank, which is its weakest part, will be transmitted to it by the outer end of the holder striking the shoulder g of the tool, which is a much larger and more rigid part of it, and therefore bet ter able to receive the blow without setting up injurious jars and vibrations. The purpose of the helical springf is to prevent injury to the striking parts should the pneumatic hammer be in motion when the tool is not in contact with the work, and it also serves to lessen the effect of vibrations set up in the apparatus by the roeiprocations of the piston.

The annular space 0 between the ring D and the rear side of the larger diameter of the piston A is used as an exhaust-chamber and communicates with the atmosphere through a passage 0 in the body 0. The piston is formed hollow or with a longitudinal cavity to serve as a cylinder within which the tappet-valve B is adapted to slide in an air-tight manner. The said tappet-valve comprises in the example now being described a cylindrical tube open at both of its ends, whereby the interior thereof is in communication with the supply of motive fluid, so as to be always filled with the said fluid. The said cylindrical tube has a flange b at its rear or inner end, this said flange, the ring D, and the end wall of the chamber 0 being so arranged that when the piston is reciprocating the flange b will come into contact with the ring in its forward stroke or with the end wall of the chamber 0 in its backward stroke just before it completes either of these strokes, thereby alternately causing the tube to move to and fro longitudinally a short distance. The motion so given to the tube causes it to act as a valve to open and close ports or passages Ct, formed in the piston, and thus alternately admit the motive fluid to the space in front of the forward end of the piston and exhaust it therefrom, such alternations, together with the constant pressure exerted upon the rear end of the piston, causing the latter to reciprocate. The said tube is also formed with a recess 1), and the said piston is formed with lateral passages or ports a, these ports and the recess being so arranged relatively to each other that when the tube is pushed forward into the position represented in Fig. 2 the motive fluid in front of the piston can escape through the ports a, the recess Z), and the ports a into the annular space 0 surrounding the smaller diameter of the piston, and thus reach the atmosphere through the ports 0 In Fig. 2 the passage 04 is shown as'having overrun the end of the ring D, thereby closing the passage. This causes cushioning of the motive fluid to occur between the piston and the end of the ring D and absorb the momentum of the piston on its rearward stroke. While the passage a is so closed, the exhaust fluid escapes through the passage 0 The said tube is also formed with another recess 19 to contain a springring 6 which operates to exert sufficient friction to insure that the valve shall not become displaced when the apparatus is inverted or shaken.

What I claim, and desire to secure by Letters Patent of the United States, is-

1. In a portable fluid-pressure hammer, the

combination with a casing constituting the working cylinder, of a reciprocating piston containedinside the casing, of a sliding tubular tappet-valve carried by the said piston and of projections situated within the cylinder and in the path of said valve for the latter to strike against as the piston performs its forward and rearward strokes, whereby the said valve is shifted in opposite directions to open and close the ports or passages and permit the motive fluid to reverse the movement of said piston at regular predetermined parts of the stroke, substantially as and for the purpose specified.

2. In aportable fluid-pressure hammer, the combination with the reciprocating piston, and the sliding valve carried thereby, of a cylindrical casing, constituting the working cylinder, formed of two detachable portions screwing one onto the other, of a fixed hollow handle connected with the rear portion of said casing by a hollow arm, of means for coupling said handle to the motive-fluid supply,

of an adjustable rotary valve located in said handle at a point to permit the thumb of the hand grasping the handle to reach and actuate said valve for regulating the supply of motive fluid to the casing, described.

3. In a portable fluid-pressure hammer, the combination with the reciprocating piston, the sliding valve carried thereby and the means for holding the tool in alinement with the said piston; of a cylindrical casing constituting the Working cylinder formed of a forward and a rear portion screwing one onto the other in a detachable manner, and of a removable ring in which the said piston reciprocates and which is held in place within said casing by pressure exerted thereon when the aforesaid two portions of the casing are screwed together, substantially as described.

4. In a portable fluid-pressure hammer, the combination with the reciprocating piston, and the sliding valve carried thereb of a cylindrical casing constituting the working cylinder formed of a forward and a rear portion screwing one onto the other in a detachable manner, of a removable ring in which said substantially as piston reciprocates, and of a flange or flanges on said ring for the aforesaid detachable member of the casing to bear against when said members are screwed together substantially as described.

5. In a portable fluid-pressure hammer, the combination with a piston constituting the hammer proper and constructed in two diameters of which the greater is forward of the lesser, of a ring in which the said lesser portion of the piston slides, of a tube adapted to slide air-tightin theinterior of said piston, and of a flange upon the rear end of said tube, having an external diameter greater than the internal diameter of said ring, said tube be ing of a length less than that of the piston, and said tube and said piston being provided with ports adapted to be opened and closed by the changes of position of the tube relatively to the piston, substantially as described.

In testimony whereof I have hereunto set my hand, in presence of two subscribing witnesses, this 27th day of November, 1900.

WALTER PAYTON.

WVitnesses:

WM. J. Dow, THOMAS SELBY WARDLE. 

